A mesoscopic inversion duplex in SW Tuscany, Italy: implications for inferring the deep geometry of collision orogens

The advances in the field of inversion tectonics illustrate that pre-orogenic extensional deformations largely control the geometry and evolution of thrust systems. While the relationships between extensional and con- tractional structures are widely documented from restoration of thrust fans, they are significantly less documented in duplex structures. In this contribution we briefly describe a mesoscopic scale duplex developed, within the Arenarie di Poggio al Carpino Fm, across a precursor boudinage structure inherited from an episode of Mesozoic age extension. The structure crops out at «I Canaloni» localty (Farma River) along the Mid Tuscan Ridge, SW Tuscany (northern Apennines of Italy).